Answer:
B. contractile vacuole
Step-by-step explanation:
Vacuoles are membrane-sized cytoplasmic structures of varying sizes formed from the endoplasmic reticulum or Golgiense complex.
The contractile vacuoles, or also with pulsatile function, are characteristic of some protozoa (paramecium) and plants, which are responsible for osmotic balance, eliminating excess water. This type can also be used as locomotor aid or excretory of some species.